Communication and data processing circuitry is highly susceptible to variations in commercially supplied electric power. The signal consistency of commercial AC power is frequently unreliable due to variations in user demand and other extraneous disturbances causing power level fluctuations, which may take the form of black outs, brown outs, or transient surges. These signal variations can significantly alter stored data and switching signals in the communication and data processing circuitry and may, in some instances, damage the integrated circuitry contained therein.
It is apparent that communication circuitry and data processing circuitry require a very reliable power source. To provide reliable power and to counteract the susceptibility of this circuitry to commercial power signal variations, uninterruptible power supplies are utilized. An uninterruptible power supply guarantees the continuity of reliable AC and/or DC power regardless of the performance of the primary commercial AC power source.
A commonly used uninterruptible power supply system to supply uninterrupted AC or DC power is the continuous-type, uninterruptible power supply arrangement. A rectifier charger powered by a commercial primary AC power source energizes a continuously operating inverter or converter circuit. The inverter or converter circuit operates continuously to supply the desired output power signal. A continuously charged battery, floated across the output of the rectifier charger, supplies the necessary DC voltage to the inverter or converter should the primary commercial AC power source completely or partially fail. The continuous-type arrangement is very reliable and utilizes very few circuit components; however, such an arrangement is usually limited to line-type regulation and is not responsive to regulate the output signal if load variations occur.
In view of the foregoing, it is desirable to have an uninterruptible power supply to supply load regulated uninterruptible power to a load which may vary.